OHV stands for "Overhead Valve". It refers to a type of piston engine whose valves are located in the cylinder head above the combustion chamber. This is in contrast to flathead engines, where the valves are located below the combustion chamber. OHV engines have a simpler camshaft drive system and smaller overall packaging compared to equivalent OHC engines. However, they have limited engine speeds and constraints on valve quantity and location.

OHV can also refer to "Off-Highway Vehicles". These are motorized land vehicles predominantly used for recreational purposes on unimproved roads, trails, and other approved use areas not suitable for conventional two-wheel-drive vehicular travel. Examples of OHVs include all-terrain vehicles (ATVs), off-highway motorcycles or dirt bikes, Utility Terrain Vehicles (UTVs or side-by-side vehicles), snowmobiles, and four-wheel-drive vehicles such as jeeps and trucks. Federal regulations require OHV operators to follow specific rules when on National Forest land, such as operating only on designated areas, roads, and trails, and having state-approved mufflers and/or spark arresters.